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| United States Patent |
5,518,365
|
|
Baets
, et al.
|
May 21, 1996
|
Radial-flow exhaust gas turbocharger turbine with adjustable guide vanes
Abstract
A radial-flow exhaust gas turbocharger turbine includes a row of
individually adjustable guide vanes, each guide vane mounted on a
rotatable shalt supported in the turbine casing. A chord of each guide
vane is not greater that a largest diameter of the shaft on which the
guide vane is mounted. When viewed in the axial direction, a profile of
each vane lies completely within a radially outer contour of the
associated shaft. This permits the design of a one-piece adjustable unit
formed of a guide vane, a rotatable shaft, and a pivoting lever. The
adjustable unit can be inserted into the casing or removed from the casing
as a single unit to facilitate installation and maintenance.
| Inventors:
|
Baets; Jozef (Baden, CH);
Zehnder; Marcel (Niederwil, CH)
|
| Assignee:
|
ABB Management AG (Baden, CH)
|
| Appl. No.:
|
212829 |
| Filed:
|
March 15, 1994 |
Foreign Application Priority Data
| Mar 25, 1993[DE] | 43 09 636.0 |
| Current U.S. Class: |
415/160; 415/163; 415/164 |
| Intern'l Class: |
F01D 017/12 |
| Field of Search: |
415/156,160,163,164
|
References Cited
U.S. Patent Documents
| 537494 | Apr., 1985 | Stevens et al. | 415/164.
|
| 2933235 | Apr., 1960 | Neumann et al.
| |
| 3069070 | Dec., 1962 | Macaluso et al. | 415/164.
|
| 3652177 | Mar., 1972 | Loebel | 415/156.
|
| 4836747 | Jun., 1989 | Hotz | 415/163.
|
| Foreign Patent Documents |
| 0196450 | Oct., 1986 | EP.
| |
| 0227475 | May., 1990 | EP.
| |
| 0378343 | Jul., 1990 | EP.
| |
| 0226444 | Apr., 1991 | EP.
| |
| 0125186 | May., 1901 | DE | 415/163.
|
| 2029859 | Feb., 1972 | DE.
| |
| 4218229 | Mar., 1993 | DE.
| |
| 0138397 | May., 1930 | CH | 415/164.
|
| 0360074 | Mar., 1962 | CH | 415/160.
|
| 0578034 | Mar., 1945 | GB | 415/163.
|
| 0820595 | Sep., 1959 | GB | 415/163.
|
| 1545904 | May., 1979 | GB.
| |
Other References
"Controller for Variable Guide Vane in Supercharger and Like", Patent
Abstracts of Japan, M-456 Feb. 25, 1986, vol. 10, No. 47, Patent No.
60-198306 dated Jul. 10, 1985.
|
Primary Examiner: Look; Edward K.
Assistant Examiner: Sgantzos; Mark
Attorney, Agent or Firm: Burns, Doane, Swecker & Mathis
Claims
What is claimed as new and desired to be secured by letters patent of the
United States is:
1. A radial-flow exhaust gas turbocharger turbine with a row of
individually adjustable guide vanes disposed in a flow duct of the
turbine, each guide vane mounted on a rotatable adjusting shaft supported
in a casing, and a pivoting lever attached to each adjusting shaft to
actuate rotation of the shaft, wherein a chord of each guide vane is not
greater than a largest diameter of an associated adjusting shaft and
wherein, when viewed in the axial direction, a vane profile of each guide
vane lies completely within a radially outer contour of the associated
adjusting shaft.
2. The exhaust gas turbocharger turbine as claimed in claim 1, wherein each
guide vane, associated adjusting shaft and pivoting lever forms an
adjustable unit of one-piece design that is removable from the turbine
casing as a unit.
3. The exhaust gas turbocharger turbine as claimed in claim 1, wherein each
adjusting shaft is provided with two axially adjacent bearing locations
between which is provided an annular space supplied with compressed air.
4. The exhaust gas turbocharger turbine as claimed in claim 1, further
comprising a plurality of connecting elements, each connecting element
coupling two adjacent pivoting levers, each connecting element having a
pivot at a point of attachment to each pivoting lever, and a distance
between the pivots of each connecting element corresponding to a center to
center distance between two adjacent adjusting shafts.
5. The exhaust gas turbocharger turbine as claimed in claim 4, wherein the
connecting elements are flat links with pins, the pins engaging in
corresponding holes in the pivoting levers.
6. The exhaust gas turbocharger turbine as claimed in claim 5, wherein each
link is of two-part design and is provided with a third pivot joint.
7. The exhaust gas turbocharger turbine as claimed in claim 4, wherein the
connecting elements are chain links of a roller chain, pins which form
each chain joint forming the pivots of the connecting element and the
pivoting levers being designed as a chain wheel.
8. A radial-flow exhaust gas turbocharger turbine comprising:
a row of individually adjustable guide vanes disposed in a flow duct of the
turbine, each guide vane mounted on a rotatable adjusting shaft supported
in a casing, wherein a chord of each guide vane is not greater than a
largest diameter of an associated adjusting shaft, and when viewed in the
axial direction, a vane profile of each guide vane lies completely within
a radially outer contour of the associated adjusting shaft;
spring means to bias each unit against a duct wall of the casing; and
a pivoting lever attached to each adjusting shaft to actuate rotation of
the shaft, wherein each guide vane, associated adjusting shaft and
pivoting lever forms an adjustable unit of one-piece design that is
removable from the turbine casing as a unit, and each adjustable unit is
axially displaceable.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a radial-flow exhaust turbocharger turbine with a
row of individually adjustable guide vanes which can be turned by means of
respective adjusting shafts supported in a casing, each adjusting shaft
being actuated by means of a pivoting lever.
2. Discussion of Background
Turbines of this kind are sufficiently well known in exhaust turbochargers,
for example, adjustment of the guide vanes at the turbine being a possible
measure. Examples of this are provided by EP 226 444 B1 or EP 227 475 B1.
The adjustable turbine guide vanes are intended to produce a larger
gradient for a given throughput. This increases the turbine power, the
turbine rotational speed and, finally, the boost pressure. In order to
prevent the adjustable vanes from jamming during "hot" operation, they
must, generally speaking, be installed with appropriate clearance.
Particularly in the closed-down condition, the flow through the gaps at
the tip and the root of the vanes can have a very disturbing effect on the
main flow in the duct. In the machine according to EP 226 444 B1, this
situation is remedied by designing the duct wall of the casing to be
axially displaceable next to the turnable blade and pressing it against
the adjustable vanes during operation.
In general, as can be seen from EP 226 444 B1 or EP 227 475 B1, the
pivoting levers are driven by a common grooved ring. This grooved ring is
rotatable and must therefore be bearing-mounted. The drive shafts of the
adjustable vanes are furthermore smaller in diameter than the chords of
the adjustable vanes. As a result, the pivoting lever must, for example in
the event of vane removal, be separated from the adjusted shaft.
SUMMARY OF THE INVENTION
The object on which the invention is based is to reduce the guidance
apparatus together with the adjusting mechanism in radial-flow turbines of
the type stated at the outset to just a few components.
According to the invention, this is achieved by virtue of the fact that the
chord (S) of each guide vane is not greater than the largest diameter of
the associated adjusting shaft and, when viewed in the axial direction,
the vane profile of each guide vane lies completely within the radially
outer contour of the associated adjusting shaft.
The advantage of the invention is to be seen particularly in the fact that
it provides the possibility of designing a guide vane in one piece with
the associated adjusting shaft and pivoting lever. The adjustable unit
thus created can be introduced into the casing or removed from the casing
as a complete unit without the necessity of access to the interior of the
casing.
It is expedient if each adjustable unit is axially displaceable and can be
pressed by spring means against that duct wall of the casing which lies
opposite the tip end of the guide vanes. It is thereby possible to avoid
guide-vane clearances at the free tip end.
If each adjusting shaft is provided with two axially adjacent bearing
locations, it is expedient to provide an annular space which can be
supplied with compressed air in the casing between the bearing locations.
It is thereby possible, on the one hand, to cool the adjusting shaft and,
on the other hand, to prevent working medium from escaping from the flow
duct to the outside via the bearing locations.
BRIEF DESCRIPTION OF THE DRAWING
A more complete appreciation of the invention and many of the attendant
advantages thereof will be readily obtained as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings, which show a
single-stage exhaust turbocharger turbine with a radial turbine inlet and
wherein:
FIG. 1 shows, schematically, a 4-cylinder internal combustion engine
pressure-charged by means of an exhaust turbocharger;
FIG. 2 shows a partial longitudinal section through the turbine;
FIG. 3 shows a front view of the turning mechanism;
FIG. 4 shows a detail view of a pivoting lever with connecting links;
FIG. 5 shows a partial view of the turning mechanism with the guide vane
cascade fully open;
FIG. 6 shows a partial view of the turning mechanism with the guide vane
cascade fully closed;
FIG. 7 shows a partial section through the bearing arrangement for an
adjusting shaft.
FIG. 8 shows a partial view of a variant embodiment of the adjusting
mechanism.
Only those elements which are essential for the understanding of the
invention are shown. The casings with the inlet and outlet lines, the
rotor together with its bearing arrangement etc. are not shown in FIG. 1,
for example. The direction of flow of the working media is indicated by
arrows.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate
identical or corresponding parts throughout the several views, the
internal combustion engine shown in FIG. 1 may be assumed to be a diesel
engine. The exhaust gases from the individual cylinders flow into an
exhaust manifold 2, in which the pressure surges are evened out. The
exhaust gases pass at a virtually constant pressure, via the exhaust pipe
3, into the turbine 4, which operates by the pressure build-up method. The
compressor 5 driven by the turbine delivers the air, induced at
atmospheric pressure and compressed, via a charge-air line 6 to a
charge-air manifold 7, from which the charge air passes into the
individual cylinders. The turbine is provided with a variable equivalent
cross-section in the form of adjustable guide vanes 18 (FIG. 2).
The gas turbine shown in part in FIG. 2 has radial inflow from a spiral to
the blading and axial outflow from the blading. The walls bounding the
duct 11 through which the air flows upstream of the rotor blades 15 are
the inner left-hand and right-hand walls of the casing 14. In the region
of the rotor blades 15, the duct 11 is bounded on the inside by the hub 12
of the rotor 16 fitted with rotor blades and, on the outside by the
approximately axially extending wall of the casing 14.
The adjustable guide vanes 18 are preferably of one-piece design with their
respective adjusting shafts 19. The shaft 19 is supported in the casing 14
in a hole 13 which passes through the casing 14. At its end protruding
from the hole, the shaft is provided with a pivoting lever 21. This lever
is of one-piece design with the adjusting shaft 19 and the guide vane 18
and may take the form of a casting, for example.
To cool the adjusting shafts 19, provision is made for compressed air to
flow around them. To make available the air required, it is possible, for
example, in accordance with FIG. 1, for a bypass line 8 with a regulating
element 9 arranged therein to be provided upstream of the compressor. This
bypass line 8 opens into the casing of the gas turbine 4. Each adjusting
shaft 19 is provided with two axially adjacent bearing locations. Arranged
between the bearing locations, in the bearing holes 13 of the casing, is
an annular space 17 into which the compressed air is introduced. While
exercising its cooling and sealing function, the compressed air flows
around the bearing locations of the adjusting shaft and, via the bearing
gaps, passes into the gas stream, on the one hand, and into the
atmosphere, on the other.
As can be seen from FIG. 2 and, especially, FIG. 4, the chord S of each
guide vane 18 is not greater than the largest diameter of the associated
adjusting shaft 19. As viewed in the axial direction, the vane profile
lies completely within the radially outermost contour of the associated
adjusting shaft. It is thus possible to remove the unit comprising the
vane and adjusting shaft from the bearing hole.
In order to avoid vane clearances at the free tip end of the guide vanes
18, each adjustable unit is designed to be axially displaceable in the
bearing hole. As can be seen from FIG. 7, the adjusting shafts 19 are
designed as hollow shafts. Spring means, here a helical spring 22, are
situated in the hollow space. These spring means are supported against a
ring 20, which is secured on the casing 14 in a suitable manner. The guide
vane tip is pressed against the opposing duct wall 23 of the casing by
these spring means.
The actual adjustment of the guide vanes 18 in the cascade is accomplished
by means of the pivoting levers 21. In each case two adjacent pivoting
levers 21 are coupled by a connecting element in order to ensure that the
levers pivot synchronously. In FIGS. 2 to 6, the connecting elements are
flat links 24 with pins. The pins engage in corresponding holes in the
pivoting levers. At the point where they are attached to the pivoting
lever 21, they form a pivot 25, as illustrated in FIGS. 4 and 5. To ensure
that all the pivoting levers execute the same angular motion, the distance
A between the pivots 25 of a connecting element must correspond to the
center distance B between two adjacent adjusting shafts 19.
In the case of the example, the links are of two-part design. At their
point of connection, the two parts 24' and 24" are provided with a third
pivot joint 26. Connecting elements of this kind can compensate for
manufacturing and installation inaccuracies and differing thermal
expansions, as illustrated in FIG. 4.
The angular adjustment of the levers is accomplished by means of actuating
means which are not shown, e.g. those known from the construction of
compressors. As can be seen from FIG. 3, it is, for example, possible for
this purpose for a piston to engage on an extended adjusting lever 21a.
Adjustment is preferably accomplished automatically as a function of the
operating parameters, such as the boost pressure, the rotational speed
etc.
FIG. 5 shows a partial elevation in which the cascade is shown in the fully
open position. The non-radial position of the vane inlet edges is of no
significance here since the air flows into the cascade from a spiral at
the correct angle anyway.
FIG. 6 shows a partial elevation in which the cascade is shown in the fully
closed position, which corresponds to the smallest part load at which the
turbine is to operate.
FIG. 8 shows a variant embodiment in which the connecting elements are
chain links 24b of a roller chain. The pins forming the chain joint are
the pivots 25 of the connecting element and the pivoting levers 21b are
designed as a chain wheel.
Obviously, numerous modifications and variations of the present invention
are possible in light of the above teachings. It is therefore to be
understood that within the scope of the appended claims, the invention may
be practiced otherwise than as specifically described herein.
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